Teenagers who use e-cigarettes have twice the risk of respiratory symptoms such as persistent cough, bronchitis, and wheeze as those who have never used the devices, a large US study has found.1

Use of e-cigarettes among teenagers is increasing dramatically, and public health experts are concerned that these devices may increase cigarette smoking. But there has been limited information on the effect of chronic e-cigarette use on respiratory health.

Researchers analysed responses to a questionnaire from 2086 teenagers aged 16 to 18 years who were taking part in the ongoing Southern California Children’s Health study, to investigate the long term effects …